I don't know I'm always assuming that the planes are more dangerous. How effective are your planes? Do they ever hit?
About 1-3% hit dangerous for vehicles in combat formations. Its from WWII statistic.
Aircraft works well by march columns or in the suppression purposes.
In game the same trend, but hit level is about 10%+ that's a overpowered, and maybe in the future patches effectiveness will be reduced.
If you want to recommend the targets for aircraft through airspotters, assign to them priority targets during air operation, they highlight this targets by flares.